Mattress



FIG. 1 is a front view of a mattress showing my new design;

FIG. 2 is a rear view thereof;

FIG. 3 is a side view thereof, the opposite side being a mirror image thereof;

FIG. 4 is a top view thereof; and,

FIG. 5 is a bottom view thereof.

The strap portions are broken away to indicate indeterminate length. 

The ornamental design for a mattress, as shown and described. 